Luzonite , Pyrite Locality: Pen-Shan Ore Body, Chinkuahshih Mine, Jui-Fang Town, Taipei County , Taiwan Province , Taiwan ( Locality at mindat.org ) Size: 5.0 x 3.6 x 2.9 cm. Luzonite is an uncommon copper, arsenic sulfosalt. This fine, rich, 3-dimensional specimen of nearly solid, reddish-gray, metallic-lustre luzonite crystals to 5 mm is nicely accented by a scattering of pyrite crystals. Luzonite is especially desirable from this now defunct quarry in Taiwan. Very rich, highly representative material of this uncommon species from this extinct locale. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Luzonite
Luzonite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula Cu₃AsS₄.
It crystallizes in the tetragonal crystal system (space group I-42m). It is a member of the Sphalerite, Stannite structural group.
Key properties: Mohs hardness 3.5; specific gravity 4.38; Black streak; Metallic, dull luster.
IMA symbol Luz, grandfathered status — known before the IMA’s founding, named in 1874.
Found in hydrothermal Cu–As–Sb-rich vein and disseminated deposits, formed at low to medium temperatures.
It is found associated with Enargite, tetrahedrite–tennantite, colusite, stannoidite, pyrite, chalcopyrite, covellite, sphalerite, bismuthinite, silver sulfosalts, silver, gold.
The name refers to Luzon Island in the Philippines.